Feedback Part 2

So why would we want feedback? Well, think of your cellphone. It has certain behaviours, like sending texts if you hit the right sequence of buttons. You would like it to keep those behaviours even if the environment your phone is in changes. The voltage from the battery, for example, changes as the battery drains. But it would suck if your phone slowed down as the battery got lower. The battery isn't the only thing…

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Feedback Part 1

Welcome to a new series on CARTOON PHYSICS! It's time to learn about FEEDBACK. As a warm-up, see if you can spot the feedback in the scene below. Well there's at least four examples of feedback here. This is something we actually call "feedback". And it is: that ringing noise happens when the sound from the speakers gets picked up by the microphone. The output becomes the input. Balancing a full tray is also a…

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Symmetry Part 3

These conservation laws are special because they are, in some sense, the most fundamental things we know about the universe. We may not know what quarks are made of or how gravity fits with electro-magnetism, but whatever theories we come up with have to conserve energy and momentum (and a few other things like charge). Since symmetry gives rise to these conservation laws, you could say it's the most important thing we know about the…

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Symmetry Part 2

To see how important symmetry is to our understanding of the universe, you need to look very closely at what's between my hands. Way, WAY closer than that... Still not close enough... There! The emptiness between the atoms and photons, the substrate everything else rests on... ...space-time itself has certain symmetries. To put it another way, the laws of physics which underpin the universe have symmetries. What I figured out (because I'm awesome)[1] is that…

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